I have a bunch of Frederick routes up on Bikely, many with plenty of climbing and cue sheets. We've got great riding out here.

For Patapsco hill riding, I put together a rough cue sheet on this thread that hits all of the major hills in the area without repeating anything. It's dubbed the Patapsco Valley Leg Breaker. There's also a hilly route I have on that thread called the West Side Fixed 50.

There's plenty of parking and hills in the Fort Valley area of the George Washington National Forest, just a bit west of Skyline Drive. Great MTBing down there as well. Beautiful area and low traffic roads. Google "Elizabeth Furnace".